I see what you all mean. But surveyors are all the time asking "where do I specify the geoid model". Actually many people only know the geoid model, and they have not idea that the is a vertical CRS.
(Probably because there is only one. Like the (small) countires with just one projection, that they don't make a clear difference between the geographic and the projected system) On Mon, 8 Jun 2026 at 23:04, Greg Troxel via PROJ <[email protected]> wrote: > "Lesparre, Jochem" <[email protected]> writes: > > >> This explains why the Danish height system DVR90 is now in EPSG as a > datum ensemble > > > > I'm not sure of the Danish situation, but for the Netherlands the only > > official realisation of the height system is the levelling > > benchmarks. The geoid provides only an approximate > > transformation. Making it two different CRSs is an interesting tweak, > > but I'm afraid it would only create more confusion. > > I think the the Netherlands situation is the same as the US (different > orthometric height definitions, different underlying datum for HAE, > different geoid models of course, but structurally the same). In both > NL and US cases, I think it is incorrect to add a CRS for [orthometric > height estimated from HAE and GEOID X]. > > (I believe, after off-list conversations with Kristian and trying to > read a report in Danish, that in Denmark, there really are additional > height system realizations.) > _______________________________________________ > PROJ mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/proj >
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